99942 Apophis was a target of intense optical and radar observing campaigns during the 2012--2013 apparition when the asteroid approached Earth within 0.097 au. Radar observations were obtained on 19 days between 2012 December 21 to 2013 March 16 Brozovic et al. (2018) and lightcurve observations were obtained on 49 days between December 23 and April 15 Pravec et al. (2014). Brozovic et al....
Asteroid Apophis rotates in an excited rotation state described by two periods, rotation and precession, with the values of 263 h and 27.38 h, respectively. Together with other spin parameters and a convex shape model, these periods were derived by [1] from photometric observations carried out in 2012/13. Radar observations are consistent with the spin state derived from light curves, and the...
On April 13, 2029, asteroid (99942) Apophis will pass within 32,000 km of Earth, offering a unique opportunity to study how Earth’s tidal forces affect asteroids, particularly those with complex internal structures. This study investigates possible mass shifts and structural changes within Apophis during its close encounter, focusing on the implications of its bilobed shape, resembling a...
The upcoming close encounter of asteroid 99942 Apophis with Earth in 2029 presents a once-in-7000-year opportunity to study the dynamics, bulk properties, and interior structure of a potential rubble-pile asteroid as it passes through Earth’s gravitational field. Numerical modeling—including via Discrete Element Methods (DEMs)—has helped to develop our understanding of the dynamics and...
The close approach of 99942 Apophis, on April 13th, 2029, will offer a wide portfolio of scientific opportunities to study a near-Earth asteroids physical and orbital properties and how these are affected by close approaches with planets. Yet, although its probability of impact with our planet was definitively ruled out in March ’21, the extraordinary event of a ~ 375 m diameter object and an...
Near-Earth asteroid (NEA) 99942 Apophis is interesting because it will make an exceptionally close approach of the Earth in 2029 at a geocentric distance of 38,000 km making it the closest known flyby by a large NEA. The International Asteroid Warning Network (IAWN) conducts campaigns to test the operational readiness of the global coalition of observers, modelers, and decision makers to...
The flyby of Apophis in 2029 offers an opportunity to prove out rapid planetary defense mission concepts from Earth orbit. We will present a mission concept developed at Lawrence Livermore National Laboratory that achieves key planetary defense objectives of characterizing Apophis with two small satellites placed in flyby orbits from GTO. The spacecraft will be equipped with 25cm aperture...
The Near Earth Object (NEO) 99942 Apophis provides a unique opportunity for an operational Planetary Defense (PD) scenario. Discovered in 2004, Apophis was initially identified as a highly hazardous asteroid that could impact the Earth. Dedicated tracking campaigns have allowed scientists to eliminate any risk of impact during the April 13, 2029 flyby; however, Apophis will pass within less...
The close flyby of asteroid (99942) Apophis on April 13, 2029 presents a unique
opportunity to achieve scientific and planetary defense goals. A multi-spacecraft
mission concept to exploit this opportunity has been developed in a collaboration
between Caltech, JPL and CNES. The Caltech-led mission is being pursued as a
privately funded venture with commercial partners. Its architecture...
An understanding of both surface and interior properties of potentially hazardous objects enables accurate characterizations of their geological and geophysical conditions for planetary defense purposes (e.g., risk assessment and impact mitigation), in addition to their formation and evolution mechanisms relevant to planetary science investigations. Asteroid 99942 Apophis will fly by Earth...
The $\sim$325-meter diameter Potentially Hazardous Asteroid (PHA) designated 99942 Apophis 2004 MN$_{\text{4}}$ will make a historic close approach of Earth on April 13th, 2029, passing within $\sim$31,634 km of Earth’s surface, $\sim$4,152 km closer than our geosynchronous satellites. This is an extraordinarily unique opportunity for collecting data on a several hundred-meter size asteroid...
The physical properties of potentially hazardous small bodies are critical for planetary defense studies. The Sq-type asteroid (99942) Apophis, an Aten asteroid with an Earth-crossing orbit, will pass within ~32,000 km of Earth on Friday April 13, 2029. This close encounter could induce surface alterations of Apophis, such as landslides and mass wasting, due to gravitational interactions with...
We define a mission concept to perform a cratering and deflection experiment at Apophis with an independent impactor spacecraft that leverages the formidable capabilities of OSIRIS-APEX as an observer. This is relevant to both planetary defense and science.
A 65kg spacecraft impacting Apophis at 7km/s will make a crater between 20-50m [1,2], and result in an excavation of 2-8m deep. This is...